Use of a mobile telephone as an Internet terminal has drastically progressed, and services as well utilizing the mobile telephone have been diversified. The recent mobile telephone, which utilizes infrared-ray communication or USB, is connectable to other peripheral terminals, and utilization thereof as a mobile terminal has been generalized. Further, the mobile telephone is inclined to increasingly process a large capacity of data.
Under such a situation, a technology of shifting a session in communication from a narrow-band mobile terminal to a terminal having a wide-band interface provided therein has already been generalized.
For example, there exists the general method in which, when a user shifts a session in communication from a narrow-band cellular terminal to the terminal having a wide-band interface such as ADSL, Wi-Fi, and WIMAX in order to view larger-screen and higher-quality video (that is, when he/her makes a handover between the terminals), the terminal to which a switchover has been made negotiates with a communication counterpart by a session protocol such as SIP, and constructs a new session.
Further, the technology has been proposed of delivering the packet to a communication terminal over PAN (personal area network) by using a plurality of communication links, and transferring the packet to the communication terminal over the PAN by using the communication link (W-CDMA etc. in the case of VoIP) in accordance with an application (Patent document 1).
Herein, the so-called PAN is a name of a network that the mobile telephone having a subscriber identifier to a mobile network, and a plurality of peripheral terminals connected to each other via a short-distance connection form, and at present, architecture thereof has been proposed in a standardization organization of mobile communication. The above-mentioned handover scheme between the terminals is a technology that is applicable in the PAN as well. Further, the so-called peripheral terminal, which is a network-correspondence terminal that is operatable in alignment with the mobile terminal, becomes connectable to the network side at the moment of making a switchover of the session with mobile terminal realized in the network side. For example, there exist a network-correspondence display, a network-correspondence speaker, etc. as a peripheral terminal.
By the way, while such technologies have been proposed, some issues at point exist therein.
For example, the technology disclosed in the Patent document 1 necessitates a plurality of the communication links when switching the session realized in the mobile terminal, for example, to the session using a plurality of the peripheral terminals together each having a video reproduction function or an audio reproduction function. For this, for example, a streaming server, being a device existing in a side where video and audio are distributed, has to analyze a streaming data itself, thereby to allot the packet to an exclusive reproduction appliance, etc. communication session by communication session, which imposes a load upon a distribution-side server.
Further, the above technology necessitate performing a data copy in an Internet side/a network-side network at the moment of distributing the streaming data etc. to a plurality of the peripheral terminals, and the data copy becomes burdensome as an amount of the data is increased. That is, the data copy demands a lot of hardware resources such as a hard disc, and a load upon a system at the time of the copying process becomes unnegligible as an amount of the data is increased.
In addition hereto, traffic is increased and a load is imposed upon the network as well at the moment of distributing the packet to a plurality of the terminals by employing means such as bi-cast and multicast.
Switching the session realized in the mobile terminal to the session using a plurality of the peripheral terminals together having respective functions necessitates installing an interface for connecting to an external network such as a mobile network into respective peripheral terminals in the reception side as well of the content, which is non-efficient in terms of a communication cost and a management of communication appliances.
Thereupon, the technology has been proposed of alleviating a load at the time of the distribution by installing another node such as a back-up device, and causing it to perform a copying process. For example, the data copying technology at the time of communication has been disclosed in Patent document 2 and Patent document 3.
[Patent document 1] JP-P2006-191514A
[Patent document 2] JP-P2005-287074A
[Patent document 3] JP-P2003-087306A